05 April - End of the 2013/14 tax year. Last day to use personal allowances, annual CGT exemptions, pension and ISA contributions for the tax year.
14 April - Return and payment of CT61 tax due for quarter to 31 March 2014
19 April - PAYE/NIC and CIS deductions due for month to 5/4/2014
30 April - Daily penalties of £10 per day may now apply for those who missed the SA filing deadline of 31st Jan 2014. Up to a maximum of £900